How to put a door into existing masonry wall? 6

[mann]

I need to cut an existing masonry wall and put a 6 foot door in the wall. What construction sequence should be followed? How will the shoring and lintel placement be handled?

 

[daveross]

1. cut a series of small holes in masonry above the lintol level.
2. install temporary steel needle beams through the holes.(ie perpendicular to the wall)
3. prop the needle beams with adjustable shores at either end. Provide cross bracing between the shores. Make sure the shores have adequate foundation.
4.At this stage, the weight of the wall should be tranferred onto the needle beams and the vertical shores.
5. cut out the masonry to the profile of the new lintol, allowing for cast in place padstones at either end.
6. cast padstones either end of the lintol. Allow to set.
7. install lintol carefully, avoiding damage to the wall.
8. ram expanding mortar into gap between top of lintol and underside of masonry, allow to set.
9. engineer to carry out inspection of the works.
10.if OK, break out wall below the lintol. cut the sides of the opening with a disk saw before starting to knock out the masonry.
10. carefully release the props and remove needle beams one at a time. engineer to monitor removal of temp. props.
11. patch up the holes for the needle beams, repair finishes.
12. Your done!!!


Hints......
spacing of needle beams will depend on condition of existing masonry and whether or not the wall is load bearing.....I suggest 4 beams equally spaced for a 6 foot opening..... Temporary and permanent works should be designed by a structural engineer.....if you use a steel lintol it will be lighter and easier to handle than concrete, hence less risk of accidental damage to the wall, but will probably need to be fireproofed..... for padstones and expanding mortar you can use quick setting additives to reduce waiting time for setting...make needle beams long enough to give reasonable working space at the wall...use only a good contractor with proper supervision and safety policy for these type of works.......if you need any more please e-mail me at dave58ross@yahoo.com.

 

[Ron]

Mann...a slightly different approach---

Purchase a pre-cast, prestressed lintel that is 8 feet long. The lintel will be sized to allow a mortar joint, top and bottom (though most of the bottom will be open). Knock out the block cells (at least one cell, preferably two adjacent cells) out above the two support points for the lintel. Thread two #3 deformed bars down into each of the hollow cells of the masonry to remain on either side of the door opening. Make sure they go all the way to the floor. Knock out the cell wall at the floor level and, using a concrete bit, drill a hole for each rod into the floor as far as you can reasonable drill it and as near to the center of the cell as practicable. Epoxy the rods in place.

Fill the cells having the rod inside with flowable grout having a compressive strength of at least 4000 psi. Fill to the underside of the anticipated lintel.

Sawcut the bottom horizontal mortar joint where the lintel will go for a distance of 24 inches in from each side of the door opening.

Using a 1/2-inch thick plywood shim on each end of the lintel (at least 1 foot long by the depth of the block)at the bottom side and three, 12-inch long by 1/2-thick shims spaced about a foot apart on the top of the lintel, start putting the lintel in on one side, rotating it horizontally as you alternately tap the block out proceeding to the other side. You should end up with the lintel in place and shimmed top and bottom, but having enough space to infill mortar between the shims. Infill the mortar in the top and over the grouted cells. Allow to cure for 24 hours, then infill the remaining mortar after removing the shims. You should now see a lintel in place with no mortar joint on its underside for a length of 6 feet or so. Now you may cut the block out of the opening to receive the door.

You could also cut out just enough space to insert a steel channel section for the "jacks" on either side of the opening and then weld a channel header to both "jacks" (be sure to make the jacks higher than the opening to allow for the header depth. Once done, cut out the masonry in the opening.

Good luck.

 

[geoffdale]

What we have found to be a decent way to do this if it can be done...
Install channel members both sides of the wall, through bolted every 24" or so, so that this acts as your lintel and temporary shoring. We then remove the wall below, and the channels can either stay in place (we normally bulkhead around them or something), or install a new lintel.
Thanks
Geoff

 

[PEinc]

I've used geoffdale's method to make a much larger opening through a thick stone foundation wall that supported an active railroad train shed and trains. The stone wall was not smooth so I grouted between the channels and the stone wall. I also pre-stressed the high strength through-bolts (actually 150 ksi Dywidag threadbars) to increase their attachment to the wall. That way, the channels supported the wall by friction (with the bolts not being counted on for shear). After installing the channels and stressing the bolts, I posted up in several places from temporary footings to the bottoms of the channels. I also steel wedged the posts to take the slack out of the system. It worked well. No trains were lost.

 

[14159]

Use geoffdale's approach. I've done that lots of times, and it works like a charm. Geez. Those other methods sound like real pains in the butt.

DBD

 

[pba]

I've used both the Dave Ross and Geoff Dale approaches. Both work well. The Dave Ross approach is the one I'd describe as traditional. It has the advantage that the props and usually the pins can be hired. I've not yet met the man who will hire me steel channels...

 

[miecz]

I detail a variation of the geoffdale method (you now have the method named after you. Our field personnel tell me that the contractor usually ignores my detail and simply cuts a hole out of the wall. The masonry stands by arching action. I was at one of our jobs recently and saw such an opening for a 3 foot door. No shores, nothing.

 

[obiwan69]

The most economical is kinda the way Jeff Says, c channel bolted above the opening such that there is room to cut out the CMU, you can use hilti wedge anchors and extend the header, furr out the inside. cut your opening and leave the steel.

Ben

 

[steve1]

I have also seen "self supporting openings" cut into masonry walls. In my case the walls were constructed of end bearing structural clay tile and the openings were cut in the shape of an arch. That is, two vertical cuts and two 45 degree angle cuts. Afterwards a steel framework was erected in the openings and the archway space was in filled with new masonry.

 

[d2TY]

Depending on the length of the opening, the requirement for concealing the lintel, and the wall construction, I have detailed geoff dale's rarely and steve1's more frequently. I have heard of the needle beam procedure, but honestly, it is not done.

If you detail the channels bolted to the wall on either side, the bolts into the wall each end should carry the reaction into the wall, or maybe add steel columns. I like the extra insurance of a bottom plate x the M.O. welded to the channels. This is a great detail for those longer spans. Consider calling for temporary shoring of the floor or roof.

For shorter unexposed spans, I have detailed a sawcut joint each side, with the horizontal legs of steel angles inserted in the joint, extended 8" each end beyond the M.O., and the steel bottom plate added.

By the way, I have never heard of padstones.

 

[BubbaJ]

I have a contractor who wants to use the "geoffdale" approach, which they are referring to as a pinch beam. I have done this before, though not in a multi-wythe wall condition. I cannot rationalize how this will work when there is structural clay tile, an air gap and 4" brick.

 

[miecz]

1. Remove a horizontal slot of grout in the brick, 3 courses above the opening

2. Install a temorary lintel to carry the brick, say a 3x3x3/16" angle.

3. Remove 5 courses of brick below the temporary lintel.

4. Follow the "Geoffdale" procedure on your structural wall.

5. Weld a 3/8" plate to the bottom of your new lintel to carry your brick.

6. Reconstruct above the lintel and remove the angle.

 

[archeng59]

I have used the channels for single and multiwythe walls with success. for CMU walls, I have used the channel on one face of the CMU using Hilti tap-con screws at 8" on center (two rows staggered if necessary) or sleeve anchors and extend the channel beyond the opening as required for bearing. I've used channels on each face of the CMU if required by the loading conditions. For multiwythe walls, I've used a channel on each side of the wall with thru bolts. if there is a known air space, I require that the bolts be tightened gradually and observations made so the masonry is not damaged and deflected laterally due to the tightening procedure. I space the thru bolts as close as possible (no less than 8 inches). If all wythes are solid masonry, I've grouted the holes if the lintel is permanent. It's worked successfully as both a permanent and temporary lintel. for a permanent lintel, I've added a steel plate across the bottom of the channels after the masonry is removed for the opening.